Many industries, such as pharmaceutical companies, dairy companies, orange juice companies, photo film suppliers and the like, have a continuing problem of the sale of outdated products. The previous method of protecting against this problem primarily consisted of printing an expiration date on the package. One disadvantage of this method has been that the printed date is easily overlooked or ignored. A person in haste may not look closely at the date on the package, or may simply forget to check each time the supply is used, as for example, when a druggist dispenses drugs from a large supply bottle to fill a small prescription for a customer. Likewise, one who does not wish to incur the additional expense involved in discarding outdated products may pass them on to an unknowing customer who cannot see the date on the supply. A further and perhaps a more critical disadvantage of the previous method is that calculation of the expiration date is made assuming that storage will be done under proper conditions. In the case of a drug which becomes impotent or perhaps even dangerous if not stored at the proper temperature, the calculation of the expiration date will assume that the storage is done at the proper temperatures. If the temperatures are not kept at proper levels, the printed expiration date is of no value in ascertaining if the drug is wholesome. Similarly, the expiration date on perishable foods assumes that storage will be proper. A product with a shelf life of many days or weeks if stored at proper temperatures may spoil in several hours if stored improperly. The present method of guarding against the sale of spoiled products by printing a pre-determined expiration date on the package is totally ineffective in these cases. It is therefore one of the principal objects of the present invention to provide a timer and storage condition indicator which can indicate expiration of shelf like, taking into consideration storage conditions such as time, temperature, humidity, light, radiation or other physical factors, and which will calculate expiration based upon those factors.
Another object of the present invention is to provide a timer and storage condition indicator which indicates expiration of time in a prominent manner such that it cannot accidentally be overlooked easily, and which is so prominent as to arouse the suspicions of persons observing it, thereby discouraging intentional disregard of the expiration date.
Yet another object of the present invention is to provide a timer and storage condition indicator which can easily be assembled, either mechanically or manually, and which can easily and simply be modified to accommodate varying physical conditions and timing lengths, thereby making it practical for both small scale packaging operations, such as local drug stores or pharmacies, as well as large scale packaging operations, such as milk bottlers or photo film producers.
Further objects and advantages of the present invention will become apparent from the following diagrams and descriptions, wherein: